Ambulatory typewriter apparatus having only one driving means



G. v. PALMER 3,353,645

AMBULATORY TYPEWRITER APPARATUS HAVING ONLY ONE DRIVING MEANS Nov. 21, 1967 4 Sheets-Sheet 1 Filed June 16, 1965 v fi/vsuro/e. GEORGE lives/v7 PAL M52 8 m, 5mz4 Nov. 21, 1967 5. v. PALMER 3, 5 45 AMBULATORY TYPEWRITER APPARATUS HAVING ONLY ONE DRIVING MEANS Filed June 16, 1965 4 Sheets-Sheet 2 mmmm v 650265 W/CENTPHLMEQ i A Nov. 21, 1967 v, PALMER 3,353,645

AMBULATORY TYPEWRITER APPARATUS HAVING ONLY ONE DRIVING MEANS Filed June 16, 1965 4 Sheets-Sheet 5 fvvE/v r02.

12/ g [1-12 GEORGE MNCENT PHLMER 89 I W, fi z Nov. 21, 1967 G. v. PALMER 3,353,645

AMBULATORY TYPEWRITER APPARATUS HAVING ONLY ONE DRIVING MEANS Filed June 16, 1965 4 Sheets-Sheet 4.

El G0 fvvsA/roe. GEORGE UNCE/vr PHLMER 14 rraQA/E Y5.

United States Patent 3,353,645 AMBULATORY TYPEWRITER APPARATUS HAVING ONLY ONE DRIVING MEANS George Vincent Palmer, 8531 Hedges Way, Los Angeles, Calif. 90046 Filed June 16, 1965, Ser. No. 464,382 8 Claims. (Cl. 197-2) This invention relates to typewriters of the kind which are adapted to move over a supporting surface while typing directly onto the same surface. More particularly, this invention relates to a power train for providing the transport movement to such a typewriter.

Typewriters of the above general style are useful in applying legends, notes, and the like to documents which cannot be conveniently inserted into the conventional carriage of ordinary typewriters. For example, certain large blueprints or drafting sheets are not readily insertable and must be hand lettered. In an attempt to supply this general need, ambulatory typewriters have previously been constructed to move across the print-receiving surface.

Patent 2,900,061 issued to me and Harley E. Pritchett described an effective device of this character, using either a self-contained motor source or electrical power, a belt drive adapted to move the typewriter in the direction of a line of typing, rotatable spheres to support the device upon the surface to which the type is applied, etc.

Generally stated, an object of the present invention is to provide an improved power train for an ambulatory typewriter.

It is another object of the invention to provide an ambulatory typewriter supported and driven by a single belt-type traction means.

It is a more particular object of the invention to provide an improved power train including a continuously energized electric motor and an improved support assembly, wherein an accurate straight line of advance is assured.

It is another object of the invention to minimize me-' chanical shock in an ambulatory typewriter to improve the movement of the typewriter across a support surface.

Another object of the invention is to provide the power train with means for adjusting the impact of a typing element with the print-receiving surface whereby mechanical shock transmitted to the typewriter is minimized as well as improving the quality of printing accomplished.

It is a more specific object of the invention to provide an improved power train wherein relative movement may be selectively arrested whereby composite characters can be printed by successive strokes of the typewriter.

A more specific object of the invention is to provide an improved power train incorporating improved means for varying the increment of typewriter advance, whereby lost motion is substantially eliminated which otherwise would contribute to transmitting mechanical shock to the typewriter.

These and other objects of the invention will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying claims and drawings, in which:

FIG. 1 is a perspective view of a typewriter according to the invention;

FIG. 2 is a bottom view of the typewriter represented in FIG. 1 showing a support assembly thereof;

FIG. 3 is an elevation view along the line 3-3 of FIG. 2 showing the traction belt drive means of the typewriter represented in FIG. 1;

FIG. 4 is an elevation view along the line 44 of FIG. 2 showing a vertically adjustable ball support portion of the support assembly;

3,353,645 Patented Nov. 21, 1957 FIG. 5 is a partly diagrammatic perspective view showing the drive and key mechanism for activating a typical key and for advancing the typewriter to a new print position;

FIG. 6 is a perspective drive pulley detail view;

FIG. 7 is a perspective variable advance control detail view;

FIGS. 8A through 8D disclose a side elevation detail of the sequence of movements of a type key linkage;

FIGS. 9A through 9D disclose in side elevation the detail of a sequence of movements of the drive linkage for advancing the typewriter across a support surface;

FIG. 10 is an end view along the line 1010 of FIG. 3;

FIG. 11 is a detail view of a portion of the variable incremental adjustment means; and

FIG. 12 is a detail of rebounding means.

In general, my power train is for an ambulatory typewriter having motive means for intermittently advancing the typewriter along a line of typing in response to actuation of the typewriter keys. In addition to a motor, the power train includes a transport assembly comprising a single endless belt and a rotatable sphere carried below the typewriter and disposed to one side of the belt. The belt and sphere are both arranged to engage the support ing surface so as to share (unequally) the weight of the typewriter. By adjusting the vertical position of the sphere, the type face impact on the surface can be adjusted. My power train further includes means for adjusting the degree of each increment of lateral advance as well as means for arresting the advance entirely.

FIG. 1 shows an ambulatory typewriter 10 having a number of keys 11 arranged to form a keyboard 12. Typewriter 10 includes an array of typing elements 13 disposed to form a downstrike segment assembly whereby each element strikes the supporting surface in the region of a common imprinting center 14. Imprinting center 14 is defined by a substantially oblong shaped opening 15 formed in a transparent alignment member or template 16. Template 16- is carried by the typewriter and inscribed so as to aid in alignment of the typewriter. While activation of any of keys 11 will serve to operate the elements 13, it also will provide a lateral advance of the typewriter across the supporting surface after impactof the type face on the surface.

Support assembly Beneath the typewriter and attached to the side frame thereof, a tractor base plate 25 and a segment assembly base plate 26 are disposed to generally receive the weight of the typewriter. Plates 25, 26 each are substantially flat members which function as a bottom frame for the typewriter. At the front edge of plate 25, a pair of tabs 27, 28 are bent downwardly and are drilled to form a journal for a pair of axles 2? and 30, respectively, which are journaled at their other ends in downwardly depending portions 31, 32.

The typewriter is supported upon the surface for movement thereacross by a transport assembly. The transport assembly includes a single endless traction :belt 17 trained around a pair of rollers 18, 19 to provide traction on the support surface. The center of gravity of the machine (as projected onto the supporting surface) will lie between a ball support 40 (described below) and the belt 17. Belt 17 is sufiiciently close to the keyboard edge of the typewriter to prevent tipping the typewriter by the downward thrust of a typists finger action. However, it is also close enough to the projected center of gravity to carry most of the weight of the machine and produce a straight line of advance. Belt 17 has a lower and upper reach respectively designated 20 and 21. The backside of belt 17 is formed with a number of teeth 22 which engage corresponding detents 23 formed in each of rollers 18, 19.

Roller 18 is mounted for rotation on axle 29 and retained thereon by a snap ring. Roller 19 is mounted on axle 30 for rotation in one direction only. Suitable unidirectional clutch means for preventing reverse rotation of roller 19 with respect to axle 30 are not shown as such means are believed well known in the art and can be enclosed within a roller 19. Roller 19 is retained on the end of axle 30 by hub member 33, and the latter is provided with a lever arm 34. Hub member 33 and lever arm 34 are fixed with respect to axle 30 and operate therewith. As will be explained further below, it is the movements of lever arm- 34 which serve to provide an incremental cyclic advance to belt 17 in order to move the typewriter.

Means are provided wherein an adjustable twist can be applied to the belt in order to derive an accurate line of movement for the typewriter. Accordingly, as shown in FIGS. 2 and 3, an elongated backing member 35 having a groove 36 extending therealong serves to receive the back side of the lower reach of belt 17. Backing member 35 is of relatively stiff resilient material which can be twisted longitudinally. For example, linen based Bakelite is quite satisfactory.

As best seen in FIG. 3, member 35 is supported by and spaced from plate 25 by pairs of adjustable standoff posts 37. Posts 37, for example, can be formed simply by using screws with washers of selected thickness interposed between member 35 and a horizontal rear edge portion 38 of plate 25. Thus, it will be readily evident that member 35 can be shimmed at each of posts 37 in order to apply an appropriate twist which will derive an accurate straight line of adavnce for the typewriter.

Means are also provided for properly tensioning the belt (FIG. 3) wherein a broad leaf-spring 39 is disposed to upwardly urge the upper reach 21 of belt 17. Spring 39 is secured to the rear edge portion 38 of plate 25.

As noted above, the belt 17 is disposed to underlie a position located slightly to the front of the machine from the center of gravity thereof. Accordingly, belt 17 carries a substantial portion of the weight of the type writer. The weight of the typewriter, however, is shared by a ball-bearing like sphere 40 mounted for universal rotation in a socket assembly 41.

Impact adjustment Sphere 40 depends downwardly to engage the supporting surface beneath the typewriter. The predetermined distance which sphere 40 extends below plate 26 is adjustable whereby the impact of a typing element striking the printing surface may be varied. As shown, sphere 40 is carried by a cylindrically shaped plastic member 42 closed at one end and open at the other. Member 42 has exterior threads and an interior recess 43. The open end of recess 43 is turned inwardly to retain the sphere 40'. Member 42 is threadably received in a flanged mounting member 45. Member 45 includes a cylindrical'portion 46- which extends through an opening in plate 26. Member 45 is secured to plate 26 by means of screws as shown in FIG. 4.

Means are further provided to lock member 42' in place. Thus, as shown in FIGS. 2 and'4, a groove 47 is formed around the periphery of member 45; A snap ring 48 fits within groove 47 and is formed with a tip 49' bent to extend radially a short way into a substantially radial hole drilled through member 45. A pointedpin 50 rests loosely in the radial hole whereby insertion of the tip 49 forces the pin 50'into engagement with the threads of member 42 to locksame in place.

When itis desired to change the vertical position of member 42, tip 49 is withdrawn from behind pin' 50 and member 42 screwed vertically by means of the wrenchreceiving detents 51 formed in the end thereof.

Motive means are provided including a drive linkage serving to intermittently establish an operative driving connection between a continuously energized electric motor and the transport assembly in response to operation of the typewriter keys. This motive means includes in general a continuously operative motor means and means for momentarily clutching in to same in a manner whereby a minimum of mechanical shock is developed.

Continuously operative power The continuously driven portion of the apparatus includes an electric motor 52 connected in a suitable manner to the on-off switch 53 shown in FIG. 1. The armature of motor 52 continuously drives an output shaft 54 which carries a suitable centrifugal clutch assembly 55. Clutch assembly 55 picks up a driving pulley 56 as it gets up to speed. Speed reduction pulley means 57 are mounted for rotation on a stub shaft 58. A driven pulley 59 is fixed to the end of a snatch roller 60. Roller 60 is formed with a plurality of axially extending notches 60a. The function of snatch roller 60 is more fully explained below.

Pulley means 57 is arranged to absorb a substantial portion of any shock encountered when a key is actuated and a pawl momentarily interposed into the continuously operative motive means. Accordingly, pulley means 57 comprises a pair of sheaves 61, 62 mounted to be rotated about a common axis and disposed in contiguous side-by-side relation. Each of sheaves 61-62 is formed of a pair of independent halves 61a, 61b and 62a, 62b. The adjacent halves 61b, 62b are fixed to rotate together and are free to move together along stub shaft 58 both toward and away from their respective other halves 61a, 62a. Readily stretchable belts 63, 64', such as of rubber, are respectively trained between the drive pulley 56 and sheave 61, and driven pulley 59 and sheave 62. The peripheral edges of each pair of sheave halves can be beveled in order to form a V-shaped channel and the belts preferably formed with an annular cross section, either circular or oval in shape. This arrangement of pulleys and belts is very similar to that used on Smith-Corona typewriters.

I have observed that low initial acceleration results Means are provided for intermittently advancing belt 17 responsive to actuation of a key 11, or the space bar 147;

While FIG. 5 shows an overall perspective view, the detail views of FIGS. 8A through 8D illustrate the structure and sequence of operation of a type bar actuating linkage. FIGS. 9A through 9D show the structure and sequence of operation of the drive linkage which serves to advance the typewriter. Since there is a certain similarity in these two linkages, description of the former will aid in understanding ofthe latter. Therefore, the type bar linkage will be described first.

FIG. 8A demonstrates an at rest condition. In FIG. 8B, a key has been depressed and the pawl interposed. FIG. 8C shows application of power to the linkage and FIG. 8D a return to an at rest condition but with a key still depressed.

FIG; 9A is at rest for the lateral advance linkage. FIG. 9B shows cocking of the advance linkage during forward movement of a typing element 13. FIG. 9C shows interposing a lateral advance pawl 2(l5'responsive to return movement of a typing element 13, and FIG.

9D shows application of power to the linkage to advance the typewriter an increment of lateral displacement.

Typing elements 13 (FIG. 5) are disposed on the ends of the type bars 67 for down-strike actuation. Bars 67 are operated through levers 63 and 69 by a downward pull on pull-rods 72').

Type bar linkage In understanding the type bar actuating linkage of FIGS. 8A. through 8D, it can be observed generally that snatch roller supplies the power or motive force to operate typing elements 13. Each of keys 11 serves to interpose a related pawl 105 into one of the notches 60a of snatch roller 60. Continued rotation of the latter then applies the downward pull to pull-rod 7 0.

Having in mind these general objectives the specific structure can be described wherein the type bar actuating linkage is designated generally by the reference numeral 71. Linkage 71 includes a key unit 72. Key unit 72 includes a key 11 having downwardly depending stem 73. Stem 73 is formed with an L-shnped extension having an upper edge urged upwardly against a resilient pad 74. Stem 73 is pivotally connected by a rivet 75 to a generally crescent-shaped member 76. Member 76 is mounted to be pivoted about a rod 77 extending transversely of the keyboard 12. Member 76 is spring loaded counterclockwise by a spring 73 connected just below rod 77 on one end and connected at its other end to a spring anchoring plate '79 carried by a transversely extending rod 80 extending across the width of keyboard 12. The lower end of member 76 carries a latch crank 81 pivoted thereto by a rivet 82. Crank 81 has a short transversely extending portion 83 which projects into a hole 84 in member 76. A spring 85 urges portion 83 against the left edge of hole 84. Latch crank 81 is further provided with an upwardly extending finger 86 formed at its top with an L-shaped seat 87.

Key unit 72 is operated by downward movement of key 11 which carries finger 86 upwardly as shown in FIG. 88. Release of key 11 returns finger 86 to its lowered position and returns key 11 upwardly until arrested by pad 74.

Upward movement of finger 86 serves to operate an interposer unit designated generally as 90. Unit 90 in cludes a T-shaped rocker 91 having three arms 92, 93, 94. Rocker 91 is pivoted by a rivet 95 through a somewhat U-shaped bell crank 96. Arm 93 has a short transversely extending portion 93a which is disposed to be received onto seat 87. In operation, upward movement of finger 86 will rotate rocker 91 counterclockwise about rivet 95. A counteracting spring tension is applied by a spring 97 connected between arm 92 and a latch member 98 pivotally carried on a downwardly extending arm 101 of hell crank 96. Member 98 is formed with a. rounded detent surface 99.

Bell crank 96 also carries an interposer plate 102 pivotally mounted thereto by a rivet 103. At the top of plate 192 there is formed a pawl 105 adapted to be moved into engagement with any of notches 60a when plate 102 is rotated clockwise about rivet 103. 'In order to rotate plate 192, the end of rocker arm 94 is upwardly curved and received in a recess 106. Upward movement on arm 93, imparted by actuation of key 11, serves to move' pawl 105 into snatch roller 60. Positive entering action of pawl 105 is assured by rounded detent surface 99 which contacts with a corresponding surface on plate 102. The movement of latch member 98 is in the nature of an over-center spring movement which insures positive engagement once appropriate movement is initiated.

Clockwise movement of plate 102 is arrested after pawl 105 is inserted into snatch roller 60. Thus a short, transvcrsely extending interposer stop dog 10 formed integrally with bell crank 96 is received by a recess 108 formed in plate 102. Each interposer unit 90 pivots generally about a rod extending transversely of the keyboard through bell cranks 96. Counterclockwise rotation thereof acts against tension of a spring 104 connected between each crank 96 and a fixed member 114.

By interposing a selected pawl into snatch roller 60, the snatch roller will drive the selected unit 90 counterclockwise about rod 100. During this counterclockwise movement pawl 105 moves downwardly until it is disengaged from roller 60, meanwhile actuating pullrod 70.

Space bar operation is provided by means of a link 145 in similar fashion, but without a typing element 13 connected thereto. Further explanation is not considered necessary in view of the foregoing description of a typical linkage 71.

Lateral advance linkage Means are provided whereby the lateral advance of the typewriter responds to operation of a selected type bar actuation linkage 71. Accordingly, a bail assembly comprised of a pair of bail levers 109a and 109]) carrying a transverse bail 110 secured in the upper ends thereof, pivots about rod 100. Bell crank 96 is further provided with a bail drive extension portion 111 which is disposed to apply counterclockwise movement of bail levers 109 during downward movement of pawl 105. The bottom of lever 109a is connected by a spring 112 to a spring anchor stud 113. Spring 112 serves to load bail 110 against extension portion 111. Operation of any one of keys 11 causes bail 110 to be carried in a direction toward the imprinting position 14. Upon disengagement of pawl 105, typing element 13 continues to move forward by inertia until it strikes a resilient wire 117 (FIG. 12) mounted to and extending across and above a bifurcated guide finger 118. Finger 118 is disposed about imprinting position 14 and serves to guide each element 13 therethrough until it strikes the print-receiving surface. At that time, wire 117 has been depressed and serves to rebound the element 13 upwardly until spring 104 takes over, as is conventional. Spring 1112 assists by moving bail 110 clockwise against extension portion 111.

The means provided for interrelating operation of a typing element and lateral advance of the typewriter further includes a stilt wire link carried at the lower end of bail lever 109a as shown in FIG. 5. Link 115 drives a generally crescent-shaped member 176 which is similar in construction to member 76 of FIGS. 8A-8D.

Where components are utilized in the lateral advance linkage, which are somewhat similar to components in the type bar actuating linkage 71, reference numerals re letting/thereto will be hereinafter designated by increasing their value by 100. Thus, the reference numeral for member 76 as shown in linkage 71 resembles member 176 of the lateral advance linkage shown in FIGS. 9A-9D. Of course, where the same structure is shared by the two linkages, as for example spring anchor plate 79, the reference numeral will be the same in both instances.

Finger 186, as best shown in FIG. 9, is normally carried so that portion 193a rides along the side thereof as distinguished from resting in seat 187. Movement of bail 110 counterclockwise as shown in FIGS. 9A-9D by actuation of any of keys 11 serves to drive link 115 to the right thereby pivoting member 176 about rod 77. This action moves finger 186 downwardly whereby portion 193a slips onto the seat 137. In this condition, the lateral advance linkage is conditioned substantially as shown in FIG. 9B so that as movement of bail 110 is reversed (by disengagement of pawl 105 from roller 60) finger 186 will be driven upwardly to interpose pawl 205 into roller 60. A pull-rod is connected to be pulled downwardly by counterclockwise rotation of bell crank 196.

Adjustable character spacing Means are provided for transmitting the downward movement of pull-rod 170 into an adjustable incremental lateral movement of the typewriter. As noted above, lateral movement of the typewriter is effected by means of rotation of axle 30 caused by upward movement of a lever arm 34 (FIG. 2). As also previously noted, suitable unidirectional clutch means is interposed between axle 30 and lever arm 34.

Means for converting downward pull of rod 170 to an adjustable upward movement of lever arm 34 comprises generally means for adjusting a moment arm of the lever so as to vary the lateral typewriter displacement. This is best shown in FIG. 7 where a drive link 120 is formed with an elongated hole 121 at its lower end. Hole 121 receives the end of lever 34 so that it can rotate axle 30. The clutch means within roller 19 is arranged whereby the roller 19 is driven only by upward movement of lever 34. Downward movement of lever 34, effected by spring 116, rotates axle 30 to return link 120 downwardly.

Means for varying the vertical movement of link 120 to adjust the increment of displacement of the typewriter includes a channeled lever arm 122 having a groove 129 therein. Arm 122 has transversely bent ends 123 and 124 and pivots about a support, such as stud 125 carried by a side plate 126 or part of the frame. End 123 is connected by a pull-rod 170 for downward movement effected by bell crank 196 (FIGS. 9A-9B). Arm 122 is spring loaded against such movement by a spring 127 which connects end 124 to side plate 126.

The upper end of drive link 120 is arranged to be moved longitudinally of arm 122. A J-shaped follower plate 130 slides along groove 129 and includes a slot 135 to receive stud 125. A hole 128 is adapted to be connected to the upper end of drive'link 120 such as by a loosely fitting rivet whereby link 120 can pivot about same.

The upper end of link 120 can be moved along arm 122 by a knurled knob 131 rotatably mounted on a stud 132. Knob 131 is conveniently located adjacent the keyboard and is adjustable therefrom. The side of knob 131 is provided with a face cam 133. A cam follower in the form of a stud 134 projects from the side of a cam follower connecting member 135. Member 135 is carried at one end by stud 132 which extends through an elongated slot 136 in member 135. At the other end, member 135 is carried by a rivet through the upper end of drive link 120. Member 135 is loaded by spring 137 to urge stud 134 into engagement with face cam 133.

Rotational movement of knurled knob 131 adjusts the increment of lateral advance by varying the moment of arm 122. As arm 122 is rocked about pivot 12 by the downward pull of pull-rod 170, axle is rotated clockwise' as viewed in FIG. 7. Regardless of the increment selected, there is always a positive and continuous connection for transmitting operative movements of arm 122 to link 120. Thus, lost motion has been substantially eliminated so that various character spacings can be selected without further contributing to mechanical jarring'of the typewriter during operation.

It should be noted that as the upper end of link 120 IS moved along arm 122, lever arm 34 receives substantially no adjustment until link 120 is pulled upwardly. Accordingly, the variable advance can be adjusted between char- :acters without moving the traction means during ad ustments of the moment arm. Such adjustments can be made both to increase as well as decrease the amount of spacing between characters.

Lateral advance arresting means While means, as just described, have been provided for varying the degree of advance of the traction means, there is also provided means for temporarily preventing advance altogether of the typewriter between successive strokes of same. The control of such means is manually operable from the keyboard, such as by an arresting button 138 (FIG. 5). In general, the mechanism for completely arresting relative movement between the typewriter and the printing surface, functions by momen- 8 ta'rily precluding the leftward return of the bottom of bail lever 109a as shown in FIG. 9B. Release of the arresting button 138 imparts an incremental lateral displacement of the typewriter by permitting levers 199 to be moved clockwise.

As shown in FIG. 5, arresting button 138 is mounted upon the top of a vertically disposed shaft 139 slidably held in a sleeve 140. The bottom end of shaft 139 rests upon a fiat transverse portion of a bail lever retaining arm 141. Bail lever retaining arm 141 rotates about a point 142. Retaining arm 141 is formed with a short, transversely extending tab 143. The broad outer surface of tab 143 is disposed to move in an arc whereby it can be brought into engagement with the edge of bail lever 109a by downward movement of shaft 139. Engagement between tab 143 and bail lever 109a serves to hold bail lever 109a from clockwise return movement as shown in FIG. 9B. During normal operation, tab 143 is disposed out of engagement with bail lever 109.

Thus, by manipulating button 138, composite characters can be formed. For example, while holding button 138 depressed, an O can be struck followed by a slant line, thereby forming the character for phi. Subsequent release of button 138 advances the typewriter by releasing bail 110.

In order to feed a ribbon, (not shown) any suitable means can be utilized. As noted above, bail lever 109 is located at each end of bail for pivotal movement about rod 100. Movements of the bottom end of bail lever 1091: can be utilized to impart the necessary incremental advance to a ribbon feed mechanism as by means of a ratchet operated by link 149.

Suitable supply and take-up rolls for the ribbon feed can be provided beneath plate 25 and fed in conventional manner to the imprinting center 14 for typing. For example, the elongated holes 144 can be utilized to carry a suitable ribbon guide to direct a ribbon across imprinting center 14.

From the foregoing description it will be evident that I have provided an improved drive train arrangement having many desirable features. My drive train arrangement operates to produce faithful straight line tracking. This tracking can be momentarily arrested entirely or, the increment of lateral advance can be increased or decreased as desired. My drive train arrangement achieves the above faithful tracking while employing continuously operative motor means as distinguished from previous impractical schemes.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the apparatus illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

I claim:

1. In a typewriter of the type which is adapted to move over a print-receiving surface, and which has a driving power train including motive means for intermittently advancing the typewriter in a predetermined direction across the surface in response to typing thereon, a transport assembly comprising a frame disposed to generally receive the weight of the typewriter, a pair of rollers driven by the motive means and spaced apart in a direction corresponding to the direction of movement of a line of typing, a single endless belt trained around said rollers for cyclic movement to move said typewriter in said direction, said single belt being the sole traction means for said typewriter, said belt serving to support said frame from said print receiving surface, and a rotatable sphere carried by said frame to continuously engage said surface to support the typewriter during typing upon said surface, said sphere being disposed laterally to one side of said belt and extending downwardly beneath said typewriter sufi'iciently whereby the weight of the type writer during typing is transmitted to said surface via said belt and said sphere.

2. Typewriter apparatus as defined in claim 1 further including means serving to vary the impact with which the type faces of the typewriter strike the supporting surface including means for adjusting said predetermined distance.

3. Typewriter apparatus as defined in claim 2 wherein said sphere is disposed between said belt and an imprinting position common to the typing elements of the typewriter, the sphere being adjacent the latter whereby the impact of printing is rendered adjustable.

4. In a typewriter of the type which is adapted to move over a print-receiving surface, and which has a driving power train including motive means for intermittently advancing the typewriter in a predetermined direction across the surface in response to typing thereon, a transport assembly comprising a frame disposed to generally receive the weight of the typewriter, a pair of rollers driven by the motive means and spaced apart in a direction corresponding to the direction of movement of a line of typing, a single endless belt trained around said rollers for cyclic movement to move said typewriter in said direction, said belt serving to support said frame from said print receiving surface, said belt including an upper and a lower reach, the lower reach being disposed to engage the printing surface, and an elongated backing member having a groove therealong serving to receive the back side of said lower reach, said backing member being supported by and spaced from said frame by pairs of adjustable standoff posts disposed to the sides of said lower reach whereby an adjustable twist can be applied to said member to derive an accurate line of movement for said typewriter, and a rotatable sphere carried by said frame to one side of said belt and disposed to extend downwardly beneath said typewriter a predetermined distance to engage said surface whereby the weight of the typewriter is transmitted to said surface via said belt and said sphere.

5. Typing apparatus as defined in claim 4 further including means for tensioning said belt comprising a broad leaf-spring arranged in sliding contact engagement with the back side of the upper reach of said belt.

6 111 a typewriter having keys arranged to form a keyboard and an array of typing elements arranged to strike a printing surface at a common imprinting center upon activation of said keys, said typewriter being further of the type which moves over said print receiving surface, the combination comprising endless belt type traction means trained to be cyclically driven to move said typewriter across said surface in a predetermined direction corresponding to the direction of progress of said printing, continuously energized electric motor means, means for establishing an operative driving connection between said motor means and said traction means responsive to operation of said keys, and means in said driving connection for absorbing substantial shock in establishing said driving connection, the last said means including a driving pulley, a driven pulley, and reduction pulley means, said reduction pulley means comprising first and second sheaves mounted to be rotated about a common axis and disposed in contiguous side-by-side relation, each of said sheaves being formed of a pair of independent halves, the adjacent halves of said sheaves being fixed to turn together about said axis and free to move along said axis toward and away from their respective other halves, and resilient readily stretchable belts respectively trained between said drive pulley and said first sheave and between said driven pulley and said second sheave.

7. A typewriter apparatus as defined in claim 6 wherein the peripheral edges of each pair of sheave halves are beveled to form a V-shaped channel, and wherein said resilient belts are of readily compressible annular cross section.

8. In a typewriter having keys arranged to form a keyboard and an array of typing elements arranged to strike a print receiving surface at an imprinting center common to all said elements, and wherein said imprinting center is arranged to move relative to said surface between successive strokes of said keys, motive means serving to provide said relative movement, and means for establishing an operative driving connection from said motive means to provide said relative movement, and means in said driving connection for absorbing substantial shock in establishing the driving connection, the last said means including a driving pulley, a driven pulley, and reduction pulley means, said reduction pulley means comprising first and second sheaves mounted to be rotated about a common axis and disposed in contiguous sideby-side relation, each of said sheaves being formed of a pair of independent halves, the adjacent halves of said sheaves being fixed to turn together about said axis and free to move along said axis toward and away from their respective other halves, and resilient readily stretchable belts respectively trained between said drive pulley and said first sheave and between said driven pulley and said second sheave.

References Cited UNITED STATES PATENTS 1,001,359 8/1911 Crowell 19783 1,458,251 6/1923 Stickney 19783 2,542,632 2/1951 Molin 197-83 X 2,717,684 9/1955 Hatter 1972 2,900,061 8/1959 Palmer et al 1972 3,190,427 6/1965 Pederson 197-2 ROBERT E. PULFREY, Primary Examiner. E. S. BURR, Assistant Examiner. 

1. IN A TYPEWRITER OF THE TYPE WHICH IS ADAPTED TO MOVE OVER A PRINT-RECEIVING SURFACE, AND WHICH HAS A DRIVING POWER TRAIN INCLUDING MOTIVE MEANS FOR INTERMITTENTLY ADVANCING THE TYPEWRITER IN A PREDETERMINED DIRECTION ACROSS THE SURFACE IN RESPONSE TO TYPING THEREON, A TRANSPORT ASSEMBLY COMPRISING A FRAME DISPOSED TO GENERALLY RECEIVE THE WEIGHT OF THE TYPEWRITER, A PAIR OF ROLLERS DRIVEN BY THE MOTIVE MEANS AND SPACED APART IN A DIRECTION CORRESPONDING TO THE DIRECTION OF MOVEMENT OF A LINE OF TYPING, A SINGLE ENDLESS BELT TRAINED AROUND SAID ROLLERS OF CYCLIC MOVEMENT TO MOVE SAID TYPEWRITER IN SAID DIRECTION, SAID SINGLE BELT BEING THE SOLE TRACTION MEANS FOR SAID TYPEWRITER, SAID BELT SERVING TO SUPPORT SAID 